code: def test_mask(self):
      wsd_sample = WSDSample(data)
      # test does the mask label work
      new = wsd_sample.insert_field_after_index("sentence", 0, "Emmm")
      new = new.delete_field_at_index("sentence", 1)
  
file_path: textflint/test/input/component/sample/test_wsd_sample.py
imports: import unittest
  from textflint.input.component.sample.wsd_sample import *
  from textflint.common.preprocess.en_processor import EnProcessor
label_desc: Use image node_id 9 for calling the TestWSDSample obj's underlying member method code with example usage: obj.test_mask() without return types